Mercruiser Alpha One, Gen 2 prop shaft rear seal r&r

mapk

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Nov 30, 2023
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3
Hi,
I'm wondering if it's possible to replace the rear seal on an Alpha1/Gen2 outdrive without pulling the bearing assembly? Seems like it might be possible to pry it out and press a new one in after removing the anode assembly and line cutter. Or not? Pulling the bearing assembly looks like one miserable job (this is a 23 year old outdrive). TIA!
 

mapk

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Nov 30, 2023
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3
I'm pretty sure there's just one seal, the other is the "line cutter" which is supposed to cut fish line to protect the seal. But I'm inclined to agree: removing it doesn't look pleasant.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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49,562
prop seals are always back-to-back seals.

one seal keeps oil in. one seal is reversed to keep water out.
 

mapk

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Nov 30, 2023
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3
Thanks! Makes sense, so, are the seals replaceable without removing the bearing carrier or prop shaft?
 

Scott06

Admiral
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Apr 20, 2014
Messages
6,439
Thanks! Makes sense, so, are the seals replaceable without removing the bearing carrier or prop shaft?
There are two seals in there - the line cutter is a seal with a metal shield intended to keep finishing line out of seal. Speaking from experience it doesn’t work …number 57 &58 here https://www.marineengine.com/parts/...-up/gear-housing-prop-shaft-standard-rotation

i just pulled my bearing carrier to do this. Some say you can drill and put in a small sheet metal screw and pull them out. This is what I started out trying, ended up pulling the carrier which takes the tool For retainer nut and a big puller , a lot of soaking with Kroil , a bit of heat. Broke my 1/2” breaker bar ended up getting a 3/4 drive one, more heat and it came out relatively easily. Also when it is apart you can check the bearing I found some evidence of water damage to bearings even though my gear oil never was milky…
 

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alldodge

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As Scott06 mentioned, a seal leak in most cases is not just a seal leak, the seal leaks because something changed
 
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